Capsular capture of silicone intraocular lenses

Anterior capsule relaxing incisions with neodymium:YAG laser for patients at high-risk for anterior capsule contraction

PURPOSE

To examine the effect of anterior capsule relaxing incisions created with a neodymium:YAG (Nd:YAG) laser on prevention of anterior capsule contraction after cataract surgery in high-risk patients.

SETTING

Hayashi Eye Hospital, Fukuoka, Japan.

DESIGN

Randomized masked clinical trials.

METHODS

Patients at high risk for anterior capsule contraction had anterior capsule relaxing incisions in either eye 3 days postoperatively. The anterior capsule opening was measured using a Scheimpflug videophotography system (EAS-1000) immediately and 1, 3, and 6 months after capsulotomy, and the percentage reduction in area was calculated. The degree of intraocular lens (IOL) decentration and tilt, posterior capsule opacification (PCO), and other complications were also assessed.

RESULTS

Of the 84 patients included, 30 had primary angle closure, 28 had pseudoexfoliation, and 26 had diabetic retinopathy. There was no significant difference in the mean opening area between fellow eyes at baseline. In patients with primary angle closure, the area was significantly greater and the percentage reduction in area was significantly less in the capsulotomy group than in the no-capsulotomy group (P≤.0428). In patients with pseudoexfoliation or diabetic retinopathy, the percentage reduction was significantly less in the capsulotomy group than in the no-capsulotomy group (P≤.0493), although there was no significant difference in area. No significant difference was found in IOL decentration or tilt, PCO, or incidence of other complications.

CONCLUSION

Neodymium:YAG laser anterior capsule relaxing incisions in the early period after cataract surgery were effective in preventing anterior capsule contraction in high-risk patients and had no adverse effects.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Posterior capsule opacification after implantation of a hydrogel intraocular lens

AIM

To compare the degree of posterior capsule opacification (PCO) in eyes with a hydrophilic hydrogel intraocular lens (IOL) with that in eyes with a hydrophobic acrylic IOL.

METHODS

Ninety five patients underwent a hydrogel IOL implantation in one eye and an acrylic IOL implantation in the opposite eye. The PCO value of these patients was measured using the Scheimpflug videophotography system at 1, 6, 12, 18, and 24 months postoperatively. The rate of neodymium:YAG (Nd:YAG) laser posterior capsulotomy and visual acuity were also evaluated.

RESULTS

The mean PCO value in the hydrogel group increased significantly (p<0.0001), while that in the acrylic group did not show significant change. The PCO value in the hydrogel group was significantly greater than that in the acrylic group throughout the follow up period. Kaplan-Meier survival analysis determined that the Nd:YAG capsulotomy rate in the hydrogel group was significantly higher than that in the acrylic group (p<0.0001). Mean visual acuity in the hydrogel group decreased significantly with time (p<0.0001), and became significantly worse than that in the acrylic group at 18 and 24 months postoperatively.

CONCLUSION

Posterior capsule opacification in eyes with a hydrophilic hydrogel IOL is significantly more extensive than that in eyes with a hydrophobic acrylic IOL, and results in a significant impairment of visual acuity.

Role of posterior capsulotomy with vitrectomy and intraocular lens design and material in reducing posterior capsule opacification after pediatric cataract surgery

PURPOSE

To study the effect of primary posterior capsulotomy with anterior vitrectomy (PPC + AV) and intraocular lens (IOL) design and material on the development of posterior capsule opacification (PCO) after pediatric cataract surgery.

SETTING

Tertiary care institution in India.

PATIENTS

Sixty-four eyes of 52 children ranging in age from 3 months to 12 years who had cataract extraction with IOL implantation were prospectively evaluated for a minimum postoperative period of 2 years.

METHODS

Thirty-two eyes received a hydrophobic acrylic lens with a truncated, square edge and 32, a single-piece poly(methyl methacrylate) (PMMA) lens that was not heparin surface modified. Sixteen eyes in each IOL group had PPC + AV; in the remaining 16 eyes in each group, the posterior capsule was left intact.

RESULTS

Postoperatively, 25 eyes in the intact capsule group and 5 in the PPC + AV group developed PCO; the difference between groups was significant (P<.05). Of eyes with an intact capsule, 12 with an acrylic IOL and 13 with a PMMA IOL developed PCO (P>.05). In the PPC + AV group, 2 eyes with an acrylic IOL and 3 with a PMMA IOL developed PCO (P>.05). Overall, 14 eyes with an acrylic lens and 16 eyes with a PMMA lens developed PCO (P>.05). After surgery, there was a significant short-term delay in the development of PCO in the acrylic group (14 eyes; mean 6.66 months +/- 1.57 [SD]) compared to the PMMA group (16 eyes; mean 3.16 +/- 0.83 months) (P<.05).

CONCLUSIONS

It is the management of the posterior capsule rather than IOL design and material that influences the incidence of PCO after cataract surgery in children. Development of PCO in the postoperative period was delayed with a hydrophobic acrylic IOL with square edges compared with a PMMA lens without square edges.

Posterior capsule opacification after cataract surgery in patients with diabetes mellitus

PURPOSE

To examine the degree of posterior capsule opacification (PCO) after cataract surgery in patients with diabetes and in nondiabetic age-matched control patients.

DESIGN

Case-control study.

METHODS

The PCO density value in 100 consecutive diabetic patients and in 100 nondiabetic age-matched control patients who underwent cataract surgery was measured using a Scheimpflug videophotography system at 1 week and at 3, 6, 12, 18, 24, 30, and 36 months after surgery. The incidence of neodymium:yttrium-aluminum-garnet (Nd:YAG) laser posterior capsulotomy was also evaluated. Furthermore, the stage of diabetic retinopathy and systemic condition of the diabetes were correlated with the degree of PCO.

RESULTS

No significant difference between the two groups was observed in the mean value of the PCO for up to 12 months after cataract surgery. However, at 18 months and later, the PCO value in the diabetic group increased significantly and was significantly greater than in the control group. Kaplan-Meier survival curves showed that diabetic patients were significantly more likely to require Nd:YAG capsulotomy than control patients (P =.0139, Mantel-Cox log rank test). Among the diabetic patients, there was no significant correlation of PCO value with the stage of retinopathy. Furthermore, type of treatment, duration of diabetes, and hemoglobin A(1C) did not correlate with the PCO value.

CONCLUSIONS

Diabetic patients developed significantly greater PCO after cataract surgery than did nondiabetic patients, but among the diabetics, the stage of diabetic retinopathy and systemic status of the diabetes did not correlate with the degree of PCO.

Changes in posterior capsule opacification after poly(methyl methacrylate), silicone, and acrylic intraocular lens implantation

PURPOSE

To prospectively evaluate the progression of posterior capsule opacification (PCO) after poly(methyl methacrylate) (PMMA), silicone, and acrylic intraocular lens (IOL) implantation.

SETTING

Hayashi Eye Hospital, Fukuoka, Japan.

METHODS

Three hundred eyes of 300 patients scheduled to have IOL implantation were initially randomized into 3 groups based on IOL type: PMMA, silicone, or acrylic. Of the 300 eyes, 269 completed the follow-up. The PCO density in these eyes was measured 1 week and 3, 6, 12, 18, and 24 months postoperatively using special computer software developed for the Scheimpflug videophotography system. Visual acuity and the incidence of neodymium:YAG (Nd:YAG) laser capsulotomy were also examined.

RESULTS

Three months postoperatively and later, the mean PCO value in the PMMA group increased significantly (P <.0001); the increase in the silicone and acrylic groups was not significant. The PCO value in the PMMA group was significantly greater than in the silicone or acrylic group (P <.0001). The PCO value in the acrylic group was slightly less than in the silicone group at 18 and 24 months, but the difference was marginal. The survival rate not requiring Nd:YAG capsulotomy was least in the PMMA group, followed by the silicone and acrylic groups in that order (P <.0001). The mean logMAR visual acuity in the PMMA group increased postoperatively and was worse than in the silicone or acrylic group.

CONCLUSIONS

The degree of PCO after PMMA IOL implantation progressed significantly with time, while the progression after silicone and acrylic IOL implantation was slight. Therefore, PCO in eyes with a PMMA IOL was significantly more extensive than in those with a silicone or acrylic IOL and resulted in marked impairment of visual acuity.

Early decentration of plate-haptic silicone intraocular lenses

We report 4 eyes of a consecutive series of 1299 that developed early decentration of a 10.5 mm diameter plate-haptic silicone intraocular lens (IOL) after uneventful phacoemulsification. All eyes had an intact continuous curvilinear capsulorhexis (CCC) with the IOL placed in the capsular bag. After an initial period of good vision, patients noted the onset of glare or monocular diplopia between 1 and 5 weeks after surgery. On examination, there was no significant anterior capsule contraction; however, the edge of the IOL optic was visible in the undilated pupil. There was adhesion between the anterior and posterior capsules at the margin of the CCC that maintained the IOL decentration. Decentration recurred in 1 eye after the IOL was rotated 90 degrees and recentered. Symptoms resolved in 3 eyes after the IOL was removed and replaced with a rigid IOL with a larger diameter optic.

Post-operative changes in the capsulorhexis aperture: a prospective, randomised comparison between loop and plate haptic silicone intraocular lenses

PURPOSE

There is disagreement regarding whether the capsulorhexis aperture always decreases or may increase post-operatively. The aim of this study was to settle the controversy concerning loop haptic silicone lenses and to learn more of the dynamics of the capsulorhexis relating to plate haptic lenses.

METHODS

We performed a prospective randomised study comparing the post-operative changes in capsulorhexis aperture in two groups of eyes implanted with either plate or loop haptic silicone intraocular lenses. All the surgery was performed, at a teaching hospital in the United Kingdom, by a single surgeon, using a standard technique of phacoemulsification. Patients were reviewed at 2 weeks and 6 months post-operatively. Digital retroillumination images of the anterior segment were captured. The area of the capsulorhexis aperture was determined by manually detecting its edge on a computer monitor.

RESULTS

Forty-eight cases were randomised. The groups were comparable for demographic variables and mean initial aperture size (p > 0.05). There was an 8.4% mean decrease in aperture size for the loop haptics, contrasting with 4.5% expansion for the plate haptics (p < 0.05). Sixty-five per cent of patients with the plate haptic underwent enlargement of the aperture, contrasting with 25% for the loop haptic lens (p < 0.05).

CONCLUSIONS

Silicone lenses with plate haptics undergo expansion of the capsulorhexis aperture more frequently than those with Prolene loop haptics.

Two year results: sharp versus rounded optic edges on silicone lenses

To evaluate the role of optic edge design of 2 silicone intraocular lenses (IOLs) in 2 year clinical results. Department of Ophthalmology, University of Vienna, Medical School, Allgemeines Krankenhaus, Austria. In this comparative clinical study, 50 eyes had phacoemulsification and implantation of a high-refractive 3-piece silicone IOL with sharp optic edges (CeeOn model 911F) (n = 25) or a 3-piece silicone lens with rounded optic edges (CeeOn model 920) (n = 25). Biomicroscopic findings, including those of specular microscopic examination of the anterior lens surface, were documented and the results analyzed. After 2 years, a significant between-group difference in posterior capsule opacification (PCO) but not in anterior capsule alterations was observed. Behind all CeeOn 911F sharp-edge IOLs, the capsule remained clear; in 2 of 23 capsules behind the CeeOn 920 rounded-edge, a neodymium: YAG laser capsulotomy had to be performed for dense central fibrotic PCO. Seven of 21 of the remaining eyes had first-degree central fibrotic PCO, 14 of 23 had peripheral mixed fibrotic and slender Elschnig pearl PCO, and 8 of 23 had second-degree peripheral PCO. Specular microscopic findings did not differ between the 2 groups. No severe IOL decentration occurred in any eye; 25% in the sharp-edge group and 40% in the rounded-edge group had minimal decentration. The silicone IOL with the sharp optic edge design was associated with significantly reduced PCO 2 years postoperatively.

Update on fixation of rigid and foldable posterior chamber intraocular lenses. Part II: Choosing the correct haptic fixation and intraocular lens design to help eradicate posterior capsule opacification

PURPOSE

Posterior capsule opacification (PCO) is one of the most common complications of cataract surgery, and there is an urgent need to reduce its incidence. Its main treatment, neodymium:YAG (Nd:YAG) laser posterior capsulotomy, may be associated with significant morbidity and is expensive. In this study, the authors ascertain the effect of posterior chamber intraocular lens (PC-IOL) fixation and various IOL designs (rigid polymethyl methacrylate [PMMA] optic and small-incision foldable designs) on the pathogenesis of PCO.

DESIGN

Prospective analysis of pseudophakic eyes obtained postmortem.

PARTICIPANTS

A total of 3493 eyes with PC-IOLs obtained postmortem and received between 1984 and 1998.

METHODS

Miyake-Apple posterior photographic technique.

MAIN OUTCOME MEASURES

Peripheral Soemmering's ring, central PCO in the visual axis, and eyes that have had Nd:YAG laser posterior capsulotomy were analyzed and scored, and these findings were correlated with the type of fixation and IOL design.

RESULTS

The degree of formation of peripheral Soemmering's ring was not influenced by IOL fixation. The acrylic design revealed relatively low Soemmering's ring scores. In contrast, central PCO and Nd:YAG laser capsulotomy scores were consistently influenced by fixation. The scores were significantly lower in eyes with in-the-bag fixation. The bag-bag fixated acrylic-PMMA design and the three modern silicone IOL designs analyzed in this study had less central PCO and lower posterior capsulotomy scores than did the PMMA IOLs.

CONCLUSIONS

The formation of peripheral PCO (the Soemmering's ring), the precursor of clinically significant, vision-threatening PCO, is not significantly influenced by the haptic fixation pattern. It is much more dependent on the quality and thoroughness of surgical cortical cleanup. Reduction of Soemmering's ring is an important goal because the retained regenerative cortical cells within this lesion are the cells of origin of PCO. The acrylic IOL design was associated with a lessor amount of peripheral Soemmering's ring as compared with all other designs. In sharp contrast to peripheral PCO, fixation of the IOL was a highly significant factor affecting the formation and quantity of central PCO-the clinically significant opacity behind the IOL optic, measured in this series either by scoring an intact retro-optical membrane or by documenting the presence of a Nd:YAG laser posterior capsulotomy orifice. The quantity of central PCO was consistently much lower in eyes with in-the-bag fixated IOLs compared with lenses with one or both haptics out of the bag. This is best explained by the fact that secure in-the-bag fixation positions the IOL optic in the best possible position to create a barrier effect. The lowest PCO rates were generally noted with the acrylic and modern silicone IOL designs.

Area reduction in the anterior capsule opening in eyes of diabetes mellitus patients

PURPOSE

To compare the extent of area reduction in the anterior capsule opening after continuous curvilinear capsulorhexis in the eyes of diabetes mellitus (DM) patients with that in the eyes of patients without DM.

SETTING

Hayashi Eye Hospital, Fukuoka, Japan.

METHODS

Ninety-one eyes of 91 DM patients and 91 age-matched eyes of patients without DM (control group) having intraocular lens (IOL) implantation were recruited for this prospective study. The DM group comprised 36 eyes with diabetic retinopathy (DR) and 55 without retinopathy (NDR). The anterior capsule opening area was quantitated using Scheimpflug photography 1 week and 1, 3, and 6 months postoperatively.

RESULTS

There was no statistically significant difference in mean anterior capsule opening area between the DM and control groups at 1 week or 1 month postoperatively. The area was significantly smaller in the DM group at 3 (P = .0221) and 6 (P = .0075) months. The percentage area reduction was also greater in the DM group than in the control group. The area in the DR group was significantly smaller than in the control group at 3 (P = .0392) and 6 (P = .0080) months. The percentage reduction in the DR group was larger than in the NDR or control group.

CONCLUSIONS

After IOL implantation, contraction of the anterior capsule opening area was more extensive in eyes of DM patients than in those of patients without DM, especially in the case of DR.

Adhesion of lens capsule to intraocular lenses of polymethylmethacrylate, silicone, and acrylic foldable materials: an experimental study

AIMS

To investigate the adhesion characteristics of several intraocular lenses (IOLs) to the simulated and rabbit lens capsule.

METHODS

Adhesive force to bovine collagen sheets was measured in water with polymethylmethacrylate (PMMA), three piece silicone, and acrylic foldable IOLs. In rabbit eyes, phacoemulsification and IOL implantation were performed. Three weeks later, adhesion between the anterior/posterior capsules and IOL optic was tested, and the capsule was examined histologically.

RESULTS

The mean adhesive force to the collagen sheet was 1697 (SD 286) mg for acrylic foldable, 583 (49) mg for PMMA, and 0 mg for silicone IOLs (p = 0.0003, Kruskal-Wallis test). Scores (0-5) of adhesion between rabbit anterior capsule and IOL optic were 4.50 (0.55) for acrylic foldable, 3.20 (0.84) for PMMA, and 0.40 (0.55) for silicone IOLs (p = 0.004). Scores between rabbit posterior capsule and IOL optic displayed a similar tendency; 4.50 (0.84) for acrylic foldable, 3.00 (1.00) for PMMA, and 0.40 (0.55) for silicone IOLs (p = 0.021). Histological observation indicated that the edge of IOL optic suppressed the migration of lens epithelial cells towards the centre of the posterior capsule. This inhibitory effect was most pronounced with acrylic foldable IOL and least with silicone IOL.

CONCLUSIONS

The acrylic foldable IOL adhered to the lens capsule more than the PMMA IOL, and the silicone IOL showed no adhesiveness. These differences seem to play a role in preventing lens epithelial cells from migrating and forming posterior capsule opacification.

Decentration and tilt of polymethyl methacrylate, silicone, and acrylic soft intraocular lenses

PURPOSE

The purpose of the study is to investigate the periodic changes regarding the decentration and tilt of the intraocular lens (IOL) and to compare any differences in the decentration and tilt among polymethyl methacrylate (PMMA), silicone, and acrylic soft IOLs.

METHODS

A total of 225 cataractous eyes undergoing IOL implant surgery were randomized into 3 groups based on the type of IOL: group A, one-piece PMMA IOL; group B, three-piece silicone IOL; and group C, three-piece acrylic soft IOL. Both the length of the decentration and the degree of the tilt of the IOL were quantitated using the Anterior Eye Segment Analysis System (EAS-1000). All eyes underwent EAS-1000 examinations at 1 week as well as 1, 3, 6, 9, and 12 months after surgery.

RESULTS

All IOLs were confirmed to be implanted accurately in the capsular bag after continuous curvilinear capsulorhexis was accomplished. No statistically significant differences were observed regarding the IOL decentration or tilt between the various postoperative periods in any of the three IOL groups. Furthermore, the differences regarding both the IOL decentration and the tilt between the three IOLs were not determined to be statistically significant throughout the observation period.

CONCLUSIONS

As long as the IOL was placed properly in the capsular bag after the continuous capsulorhexis, neither the decentration nor the tilt of the IOL showed a significant progression up to 12 months after surgery. Furthermore, both the extent of the decentration and tilt almost were the same among the PMMA, silicone, and acrylic soft IOLs.